When compat canonicalize_file_name was introduced, it was limited to
C code only because it was used by C code only during that time.
>From 5ec6fd4d, (lib/open: check for split configuration when creating
database., 2021-02-16), lib/open.cc, which is C++, relies on the
existent of canonicalize_file_name.
However, we can't blindly enable canonicalize_file_name for C++ code,
because different implementation has different additional signature for
C++ and users can arbitrarily add -DHAVE_CANONICALIZE_FILE_NAME=0 to
{C,CXX}FLAGS.
Let's move our implementation into a util library.
Helped-by: Tomi Ollila <tomi.ollila@iki.fi>
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
